ビットコイン（Bitcoin）用語集

Ethereum

Ethereum, developed by Mr. Vitalik Buterin is a new software platform. The virtual currency used on this platform is also called Ethereum (ETH).

While Ethereum is currently using a Proof of Work (abbreviated as PoW) algorithm for the issuance of currency to miners, there is a possibility of moving to Proof of Stake (PoS) where the difficulty of mining is adjusted based on the amount of that currency the miner possesses as well as the amount of time that it has been held.

History of Ethereum

・Launched through an ICO in July 2014

Ethereum raised an equivalent to 1.6 billion JPY through an ICO.

・Ethereum released in July 2015

Ethereum had four development phases. The first one was called Frontier.

・Updated in March 2016

This was the second development phase; known as Homestead.

・The DAO incident in June 2016

This incident occurred when the German company, Slock.it, launched its distributed autonomous investment fund smart contracts called The DAO. It was hacked; resulting in an equivalent of 6.5 billion JPY in Ethereum being stolen.

・Split into Ethereum and Ethereum Classic in June 2016

In response to the hacking in the DAO incident, a hard fork was implemented on the blockchain to restore everything to where it was before the hack occurred. However, due to there being pros and cons of this hard fork, the developers who objected to the hard fork split off into Ethereum Classic.

・Updated in October 2017

This was the third development phase; known as Metropolis.

The Metropolis upgrade is split into two stages, Byzantium and Constantinople. Byzantium went into effect in October 2017. The implementation date for Constantinople has not yet been decided.

Features of Ethereum

Implementation of smart contracts

The primary feature of Ethereum is to record the contents of a contract on a blockchain and to automatically execute it on the settlement date. These types of contracts are called smart contracts.

Since Bitcoin cannot execute smart contracts, it can only record simple transactions such as “3 BTC paid to John Doe.”

On the other hand, Ethereum records transactions which are executed by smart contracts such as “pay 3 ETH from my account to John Doe in 1 year.” One year later, the “pay 3 ETH” transaction is automatically executed through a smart contract. In addition to finance, smart contracts are also used for goods trading as well as real estate transactions.

Decentralized applications

Distributed applications (DApps) can be built by using smart contracts on the Ethereum platform.

DApps are applications that are run without a central administrator such as a company or bank.

Data management is distributed among all participants using the DApp, allowing everyone to participate in decision-making and updates.